#include "Penta6NodeShpFunc.h"

using SG::DataStructure::Common::Real;
using SG::Algebra::Matrixd;
using SG::FEMSolver::Element::Penta6NodeShpFunc;

Penta6NodeShpFunc::Penta6NodeShpFunc ()
:NSet (), DNDxiSet ()
{}

/** @brief 计算积分点处形函数及形函数对参数坐标导数
 * 
 * 缓存各个积分点处的计算结果，避免下一次积分点循环时重复计算（内存换取计算时间）
 */

void Penta6NodeShpFunc::Compute (const SG::DataStructure::FEM::IntegPointArray& integPoints)
{
    const auto nGauss = integPoints.size ();
    NSet.resize (nGauss);
    DNDxiSet.resize (nGauss);
    for (std::size_t index = 0; index < nGauss; ++index)
    {
        const Real& xi{integPoints[index].m_x};
        const Real& eta{integPoints[index].m_y};
        const Real& zeta{integPoints[index].m_z};

        NSet[index] = Matrixd (6, 1);
        NSet[index] (0, 0) = 0.5 * xi * (1.0 - zeta);
        NSet[index] (1, 0) = 0.5 * eta * (1.0 - zeta);
        NSet[index] (2, 0) = 0.5 * (1.0 - xi - eta) * (1.0 - zeta);
        NSet[index] (3, 0) = 0.5 * xi * (1.0 + zeta);
        NSet[index] (4, 0) = 0.5 * eta * (1.0 + zeta);
        NSet[index] (5, 0) = 0.5 * (1.0 - xi - eta) * (1.0 + zeta);

        DNDxiSet[index] = Matrixd (3, 6);
        DNDxiSet[index] (0, 0) =  0.5 * (1.0 - zeta);
        DNDxiSet[index] (1, 0) =  0.0;
        DNDxiSet[index] (2, 0) = -0.5 * xi;

        DNDxiSet[index] (0, 1) =  0.0;
        DNDxiSet[index] (1, 1) =  0.5 * (1.0 - zeta);
        DNDxiSet[index] (2, 1) = -0.5 * eta;

        DNDxiSet[index] (0, 2) = -0.5 * (1.0 - zeta);
        DNDxiSet[index] (1, 2) = -0.5 * (1.0 - zeta);
        DNDxiSet[index] (2, 2) = -0.5 * (1.0 - xi - eta);

        DNDxiSet[index] (0, 3) =  0.5 * (1.0 + zeta);
        DNDxiSet[index] (1, 3) =  0.0;
        DNDxiSet[index] (2, 3) =  0.5 * xi;

        DNDxiSet[index] (0, 4) =  0.0;
        DNDxiSet[index] (1, 4) =  0.5 * (1.0 + zeta);
        DNDxiSet[index] (2, 4) =  0.5 * eta;

        DNDxiSet[index] (0, 5) = -0.5 * (1.0 + zeta);
        DNDxiSet[index] (1, 5) = -0.5 * (1.0 + zeta);
        DNDxiSet[index] (2, 5) =  0.5 * (1.0 - xi - eta);
    }
}